Arctic cold covering most of the country broke a record Wednesday in Baltimore, and abnormally frigid weather is expected to last into the weekend.
Baltimore-Washington International Thurgood Marshall Airport reported a low of 19 degrees early Wednesday, one degree below a record set in 1936. Temperatures rose above the freezing mark for the first time in 36 hours in the afternoon. They reached 36 degrees just before midnight, one degree above the coldest recorded high for Wednesday's date, set in 1880.
With winds shifting to be southerly late Wednesday, temperatures are expected to moderate slightly Thursday, with highs in the lower 40s. Temperatures reached 39 degrees by 10 a.m. Thursday at BWI. But lows are forecast in the 20s again Friday and Saturday mornings.
This week's wintry weather came as state highway crews are gearing up for frozen precipitation, introducing new equipment, including nine "monster" snowplow trucks, laser sensors for measuring pavement conditions and new methods to limit salt use. Some forecasters have predicted a harsh, snowy winter, while official government forecasts are less certain.
An area of high pressure over the middle of the country has brought northerly winds carrying frigid Arctic air that broke temperature records across the eastern United States and created record demand for energy in November.
For a second straight day, freezing weather stretched across the nation. Record lows were reported across the eastern third of the country, from the Gulf Coast to southern New England. At Dulles International Airport in Northern Virginia, the temperature dropped to 13 degrees early Wednesday, 7 degrees below the previous record. Reagan National Airport outside Washington hit 22 degrees; the record low for the date is 18.
The cold helped fuel a year's worth of lake-effect snow in western New York state, blamed in the deaths of six people and stranding motorists. The region, already under as much as 5 feet of snow, braced for more heavy snow Wednesday night.
PJM Interconnection, the operator of the biggest power grid in the United States, said Wednesday that demand for power during the cold weather set a record for the month of November.
PJM, which operates the grid in 13 states from New Jersey to Illinois, including Maryland, said it has been taking steps to prepare for the winter season, including testing of generating equipment and improving coordination with the gas pipeline industry. Several power plants in the grid were unable to operate on the coldest days last winter because there was not enough natural gas due to pipeline constraints to fuel the power units and heat homes and businesses.
In Baltimore, temperatures were about 20 degrees below normal Wednesday, a rare but not unheard-of chill. It has only been a year since such November cold was observed here, with lows of 22 degrees and 19 degrees Nov. 24 and 25, according to the National Weather Service. Record lows here this time of year are in the teens to lower 20s.
"Usually, temperatures can be pretty variable this time of year," said Carl Barnes, a meteorologist with the weather service's Baltimore-Washington forecast office in Sterling, Va. "As we get into December and January and February, that's when we start to have the cold weather every day."
With the low temperatures bringing back uncomfortable memories from last winter, the coldest in the region in decades, State Highway Administration officials say they are readying for the possibility of another icy, snowy winter.
The nine new "monster" plow trucks are larger than typical plow trucks and can carry more than twice as much salt and 50 percent more fuel. They cost $200,000 each.
"Having the extra fuel capacity to remain on the roads for double the time as a standard truck is critical when storms are producing an inch or more of snow an hour," SHA Administrator Melinda B. Peters said in a statement.
The administration also is introducing sensors that are mounted on poles and shine lasers into the pavement to detect temperature and measure salt, ice and snow. Existing sensors are embedded in roadways and wear out. The SHA has installed 35 of the new sensors and plans to install 100 more by the end of the year.
Crews plan to continue increasing the use of brine solutions that leave a film of salt on pavement, as well as pre-wetting and treating rock salt so it adheres better to roads. The state has 380,000 tons of salt and 900,000 gallons of salt brine.
Despite the cold, no wintry precipitation is imminent in the Baltimore area. Dry conditions are forecast through the weekend, until a system of Gulf moisture arrives Sunday night into Monday.
The high pressure system that is now pumping Arctic air into the region will have moved off the Atlantic coast by then, and a southerly flow of warm, humid air is expected to bring a brief turnaround Monday, with highs in the mid-60s.
A return to seasonable weather, if not slightly colder than normal, is forecast ahead of Thanksgiving, with temperatures mostly in the 40s for the holiday.
Reuters contributed to this article.